// This code is derived from jcifs smb client library <jcifs at samba dot org>
// Ported by J. Arturo <webmaster at komodosoft dot net>
//  
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
using System.IO;

namespace SharpCifs.Smb
{
    public class SecurityDescriptor
    {
        public int Type;

        public Ace[] Aces;

        public SecurityDescriptor()
        {
        }

        /// <exception cref="System.IO.IOException"></exception>
        public SecurityDescriptor(byte[] buffer, int bufferIndex, int len)
        {
            Decode(buffer, bufferIndex, len);
        }

        /// <exception cref="System.IO.IOException"></exception>
        public virtual int Decode(byte[] buffer, int bufferIndex, int len)
        {
            int start = bufferIndex;
            bufferIndex++;
            // revision
            bufferIndex++;
            Type = ServerMessageBlock.ReadInt2(buffer, bufferIndex);
            bufferIndex += 2;
            ServerMessageBlock.ReadInt4(buffer, bufferIndex);
            // offset to owner sid
            bufferIndex += 4;
            ServerMessageBlock.ReadInt4(buffer, bufferIndex);
            // offset to group sid
            bufferIndex += 4;
            ServerMessageBlock.ReadInt4(buffer, bufferIndex);
            // offset to sacl
            bufferIndex += 4;
            int daclOffset = ServerMessageBlock.ReadInt4(buffer, bufferIndex);
            bufferIndex = start + daclOffset;
            bufferIndex++;
            // revision
            bufferIndex++;
            int size = ServerMessageBlock.ReadInt2(buffer, bufferIndex);
            bufferIndex += 2;
            int numAces = ServerMessageBlock.ReadInt4(buffer, bufferIndex);
            bufferIndex += 4;
            if (numAces > 4096)
            {
                throw new IOException("Invalid SecurityDescriptor");
            }
            if (daclOffset != 0)
            {
                Aces = new Ace[numAces];
                for (int i = 0; i < numAces; i++)
                {
                    Aces[i] = new Ace();
                    bufferIndex += Aces[i].Decode(buffer, bufferIndex);
                }
            }
            else
            {
                Aces = null;
            }
            return bufferIndex - start;
        }

        public override string ToString()
        {
            string ret = "SecurityDescriptor:\n";
            if (Aces != null)
            {
                for (int ai = 0; ai < Aces.Length; ai++)
                {
                    ret += Aces[ai] + "\n";
                }
            }
            else
            {
                ret += "NULL";
            }
            return ret;
        }
    }
}
